<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Bootstrap 101 Template</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link href="css/bootstrap.min.css" rel="stylesheet" media="screen">
  </head>
  <body>
    <select>
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
</select>
 
<select multiple="multiple">
  <option>1</option>
  <option>2</option>
  <option>3</option>
  <option>4</option>
  <option>5</option>
</select>
  
   <input type="submit" value="主要" class="btn btn-primary  btn-block" style="width:150px">
  </body>
</html>
